Method for measuring in vivo hematotoxicity with an emphasis on radiation exposure assessment

A method for enumeration of blood cells and blood platelets to assess the degree of hematotoxicity resulting from exposure to a hazardous exogenous agent, the method comprising:

• providing a blood sample from a mammal exposed to a hazardous exogenous agent, the blood sample comprising erythrocytes, reticulocytes, nucleated cells, and platelets;
• first contacting a portion of the sample of known volume with a nucleic acid dye that has a fluorescent emission spectrum and differentially labels mature erythrocytes, reticulocytes, nucleated cells, platelets, and leukocytes based on their nucleic acid content;
• second contacting the portion of the sample with a second fluorescent reagent that is responsive to mitochondrial membrane potential and thereby differentially labels healthy and damaged cells, the second fluorescent reagent having a fluorescent emission spectrum that does not substantially overlap with the fluorescent emission spectrum of the nucleic acid dye;
• exciting the nucleic acid dye and second fluorescent reagent with light of appropriate excitation wavelength;
• and
• detecting the fluorescent emission and light scatter produced by erythrocytes, reticulocytes, platelets and nucleated cells in the portion of the sample, and counting both (i) the frequency of one or more cell types with and without dysfunctional mitochondria, the cell type being selected from the group consisting of reticulocytes, platelets, reticulated platelets, and leukocytes;
• and (ii) the absolute number of one or more cell types selected from the group consisting of reticulocytes, platelets, and leukocytes,
• wherein the counting assesses the degree of hematotoxicity resulting from exposure to the hazardous exogenous agent.